I’ve seen this before. Crossword editors, quirky sense of humour. Probably some kind of inside joke.

In other words, a harmless conspiracy. But, for both of them, the coincidence is evidence of agency (as in intended action, not necessarily on the part of the CIA), whether in the name of pranking or murderous treason.

What are the chances, though, of such concurrences being merely happenstance?

The Times’s archive editor and feedback nabob Rose Wild has tackled this head on, in response to a reader who solves the Times2 quick crossword and that of another, unidentified, paper that he gets free at the gym. Not cryptics in this case, but the same thing is happening: “Over the course of a week or so, both puzzles include a number of the same answers.”

Each puzzle selects about 25 words from, say, about 80,000 suitable for such a puzzle, leading to a probability of a particular word in one puzzle appearing in another of 25/80,000.

But, Grimshaw goes on, the odds of a coincidence are much higher in practice, because, as we saw here in some wonderful data journalism, some words appear much more often in crosswords than they do in what non-solvers might call “real life”.

There are lots of Is and Os knocking about in words, whether in puzzles or the written word, but puzzles need words to intersect with these letters. So, crossword English has far more words that end in I or O than does the normal version of the language. Grimshaw expands:

There are similar effects that probably mean the selection is very much biased towards some types of words cropping up more often, especially where there are few possibilities to match crossing letters in longer words that can’t be changed as easily.